ejc34710

I really hope someone can help me out here. My brother has a Savage x that is going through diff gears like there's no tomorrow. At first, the ring and pinions kept breaking, so we replaced both front and rear with bullet proof diffs. Now, its eating up diff gears (has the 4 bevel conversion diffs) like crazy. It has done this since he got it, even with the stock ring and pinion. Only takes about 4 tanks of fuel, sometimes as little as 1 and you can start to hear the diffs clicking. It is ususlly the front but the back is guilty of it as well. I have no idea whats going on here and it is FRUSTRATING. Im tired of tearing this thing apart evey week to change the gears. He is getting close to trading it for a t-maxx, thats how bad it is. Any help would be appreciated, as im close to throwing this thing across the front yard.

Shenanigans

My Feedback: (12)

Dont throw it yet...there has to be an explanation...what kind of grease/oil are you running in the diffs?  Have you tried shimming the diffs?

cswtornado

When it doubt, replace everything.
Diff cases are cheapl

megamaxx

i have to ask,what are you guys doing to it in those 4 tanks of fuel? jumping houses,endless donuts,please a little background on the kind of running you are doing

ejc34710

Were hardly even bashing it. Just speed runs on the road and driving around in the grass, thats it. The diffs are shimmed but to my understanding that is for the mesh on the ring and pinion. Have not tried replacing the diff housing, but everything else is new. Engine is the stocker. I've been into rcs for 20 ears, usually i do not get stumped like this, which is why i posted. Thanks for the replys.

Oh yea, im just using automotive wheel bearing grease. I posted asking if that was ok to use, everyone said yes, i dunno.

Shenanigans

My Feedback: (12)

You should'nt be ruining the diffs with what you have setup.....I would guess the housing is somehow off from factory maybe?  Have you contacted HPI?  Maybe they'll send you some freebies.

ejc34710

No, he got the truck off craigs list, so didn't bother contacting hpi. Didnt think they would help. Im bummed. He's stopping by our LHS on the way home from work to get more bevels. Maybe it would help to mention that the gears arent like getting eatin up, just wore down enough to where they can slip.

Shenanigans

My Feedback: (12)

Hmm..bummer indeed.  Personally I would look to buy a couple new diff housings.  No point in buying new diffs since you've already gone through a couple (BP's especially).  Problem must lie somewhere other than the diff itself.

ejc34710

Yea, i'll try out the new housings. Might as well. It acts like one of the diffs is spinning at a slightly different rate that the other, so it's taking out the weakest link: the bevels in the diff. Don't see how thats possible though. Thanks everyone for your comments, i'll let you know if the housing solve the problem....

sharkattack99

get the flux composite diff housings stronger yes i know there flux but they will fit in the x or xl as well.

ejc34710

Thanks shark, good call.. Hopefully they're not as expensive as the aluminum ones.....

sharkattack99

http://www.tcscrawlers.com/HPI-Compo...2-p-17463.html

there out right now but thats the ones

ejc34710

I'm not familiar with the Flux, but i beleive those are bulkheads. The part we were referring to was the actual housing. It contains the 6 diff gears and is bolted to the ring gear. Unless i'm missing something, which is likely....

sharkattack99

oh oh ok i miss understood you that was my fault never mind then

jbooker82

My Feedback: (4)

Are you putting the thin metal washers / shims behind the gears?

ejc34710

No, well kinda. I put the shims in between the bearing on the diff cup and the diff cup itself. Then on the other side of the diff they are on the ring gear, before i put the bearing on. In other words, all the shims are on the outside of the diff. I followed instructions on the thread "how to shim diff gears for the savage" a thread posted on these forums. I was thinking that the shims installed this way would pull the diff gears apart just a tad, leaving enough play for the bevels to strip, but surely someone would of had this problem before me. Unless, that is, i'm put the shims in the wrong place.....

bigdogkanicsar

how tight is the slipper on the spur gear?
that and all of the above

jbooker82

My Feedback: (4)

Generally you add shims to the ring gear side to tighten up the mesh between the ring and pinion. I thighen mine up until they feel slightly notchy. Then just let them wear in.

The part I was talking about earlier was inside the aluminum diff cup / housing. There should be thin flat washers behind the two large bevil side gears, and behind the 4 small spider / bevel gears. There should also be an o ring behind the. Two side bevil gears and flat thin washers. They seal the drive cups and keep grease from leaking out around them. If they are missing that could also cause excess play.

ejc34710

There are no washers inside the diff cup, only the 2 rubber o rings.

ejc34710

The only time washers get used in the diff cup is if they are the aluminum diff cups. Mine are the plastic ones, so they are put together right.

megamaxx

last time i had a problem like this one, it was due to bad bearings allowing the diff to move just enough to chew them up

jeepster820

If you are using plastic diff cups with the bullet proof ring and pinion i would get aluminium diff housings

ejc34710

Ok, so we got it fixed. He went to the LHS and got some of the aluminum diff cups and new diff gears and its held up to about 12ish tanks so far. Must have been the diff cups. We shouldnt have any more problems at all anymore cause he also got bulletproof diff gears ordered, and already has bulletproof ring and pinions front and rear and the aluminum diff cups. What a PITA thou-gh. Sheesh. Thanks everyone for the help. He also got the 3 speed-there is no sweeter sound than hearing a nitro shift through three gears. My t-maxx still faster though muahahahaha .